Method and System for Installing a Water Storage Device

ABSTRACT

The present invention relates to a method and system for correctly installing a flexible liner in a tank for water storage. The present invention in the preferred form relates to the use of a substantially rigid outlet ( 20 ) in the flexible liner ( 12 ) that is received in a tank aperture ( 22 ) when the liner ( 12 ) is correctly installed in the tank ( 14 ).

FIELD OF THE INVENTION

The present invention relates to a method and system for correctly installing a flexible liner in a tank for water storage. In particular, although not exclusively, the invention relates to the use of an outlet in the flexible liner that is received in a tank aperture when the liner is correctly installed.

BACKGROUND TO THE INVENTION

The use of a flexible liner to store hot water is described in New Zealand Patent No. 244107. The flexible liner is ideally constructed from plastic or polymer material(s) and is located in the interior of a rigid tank structure. The liner functions to store hot water while the rigid tank provides structural integrity to the construction as a whole. This construction reduces heat loss from the stored water and, in combination with the use of cost-efficient plastics and composite material in its construction, is an advantageous alternative to conventional hot water cylinders.

However due to the flexibility of the liner, precise installation of the liner within the tank is difficult. Without proper liner installation, the risk of failure of the water storage greatly increases. For instance, the liner may remain displaced to one side of the tank once installed. In an incorrect position such as this, excessive stress can be placed on the joints and seams of the liner when the liner is filled with water. This stress often leads to premature liner failure.

It is therefore an object of the present invention to address the above problem or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION

As used herein, the term ‘substantially rigid extension’ denotes an extension that is rigid or semi-rigid in at least one part of the extension. The entirety of the extension need not be rigid. It is sufficient for one part, for instance the base of the extension, to be rigid or semi-rigid.

In one aspect the invention comprises a method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a base, the method comprising the steps of:

-   -   providing at least one substantially rigid extension attached to         and extending outwardly from the liner base;     -   providing at least one aperture in the tank base;     -   locating the liner inside the tank; and     -   inserting the substantially rigid extension through the tank         aperture,     -   wherein the substantially rigid extension and aperture are         positioned such that the liner     -   is correctly positioned in the tank once the extension is         inserted through the aperture.

In another aspect the invention comprises a method of installing a flexible liner into a tarik for water storage, wherein each of the liner and tank has a base, the liner base having a substantially rigid extension extending outwardly and the tank base having an aperture to receive the substantially rigid extension, the method comprising the steps of:

-   -   locating the liner inside the tank; and     -   inserting the liner extension through the tank aperture,     -   wherein the substantially rigid extension and aperture are         positioned such that the liner is correctly positioned in the         tank once the extension is inserted through the aperture.

In another aspect the invention comprises a method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a wall, the method comprising the steps of:

-   -   providing at least one substantially rigid extension attached to         and extending outwardly from the liner wall;     -   providing at least one aperture in the tank wall;     -   locating the liner inside the tank; and     -   inserting the substantially rigid extension through the tank         aperture,     -   wherein the substantially rigid extension and aperture are         positioned such that the liner is correctly positioned in the         tank once the extension is inserted through the aperture.

In another aspect the invention comprises a method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a wall, the liner wall having a substantially rigid extension extending outwardly and the tank wall having an aperture to receive the substantially rigid extension, the method comprising the steps of:

-   -   locating the liner inside the tank; and     -   inserting the liner extension through the tank aperture,     -   wherein the substantially rigid extension and aperture are         positioned such that the liner is correctly positioned in the         tank once the extension is inserted through the aperture.

Preferably the liner extension allows fluid communication into and/or out of the liner. In this form the substantially rigid extension may function as a water inlet/outlet of the liner. Most preferably, the substantially rigid extension functions as a water outlet of the liner.

Preferably the liner extension is located substantially in the centre of the liner base, and the aperture is located substantially in the centre of the tank base.

In one form, two or more extensions and apertures may be provided. Where two extensions and apertures are provided, one extension functions as a water inlet and the other extension functions as a water outlet.

Preferably the liner includes a fitting that detachably receives the substantially rigid extension.

Preferably the fitting includes an aligning means to receive the substantially rigid extension.

In a further aspect, the invention comprises a water storage system comprising

-   -   a tank having a base, the tank base having at least one         aperture; and     -   a flexible liner having a base and positioned in the tank to         store water, the liner base having at least one substantially         rigid extension attached to and extending outwardly from the         liner base;     -   wherein the substantially rigid extension extends through the         tank aperture to correctly position the liner in the tank.

In a still further aspect, the invention comprises a water storage system comprising

-   -   a tank having a wall, the tank wall having at least one         aperture; and     -   a flexible liner having a wall and positioned in the tank to         store water, the liner wall having at least one substantially         rigid extension attached to and extending outwardly from the         liner wall;     -   wherein the substantially rigid extension extends through the         tank aperture to correctly position the liner in the tank.

Preferably the liner extension allows fluid communication into and/or out of the liner. In this form, the substantially rigid extension may be a water inlet/outlet. Most preferably, the substantially rigid extension functions as a water outlet of the liner.

Preferably the liner extension is located substantially in the centre of the liner base, and the aperture is located substantially in the centre of the tank base.

In one form, two or more extensions and apertures may be provided. Where two extensions and apertures are provided, one extension functions as a water inlet and the other extension functions as a water outlet.

Preferably the liner includes a fitting that detachably receives the substantially rigid extension.

Preferably the fitting includes an aligning means to receive the substantially rigid extension.

The term ‘comprising’ as used in this specification and claims means ‘consisting at least in part of’, that is to say when interpreting statements in this specification and claims which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in this specification, individually or collectively, and any or all combinations of any two or more said parts, elements or features. Where specific integers are mentioned herein that have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE FIGURES

Preferred forms of the method and system of the invention will now be described with reference to the accompanying figures in which:

FIG. 1 is an exploded view of the water storage system;

FIG. 2 shows the flexible liner installed inside the tank;

FIGS. 3A-3F show variants of the interior tank base shape and aperture layout;

FIG. 4 is an exploded view of another form of the water storage system;

FIG. 5 shows the flexible liner installed inside the tank for the water storage system shown in FIG. 4;

FIG. 6 shows a cross-section of the joining of the liner to the top of the tank;

FIG. 7 shows an example flange for the joining shown in FIG. 6; and

FIG. 8 shows a cross-section of a liner extension.

DETAILED DESCRIPTION OF THE PREFERRED FORMS

Referring to FIG. 1, the water storage system of the invention is shown generally as 10. The system 10 includes a flexible liner 12 and a rigid tank 14. The figure shows an exemplary form of the tank and liner that is cylindrical in shape with a circular cross-section. Those skilled in the art will appreciate that this specific form is not essential, and numerous variations can be employed. For instance, a spherical or frustoconical liner/tank as taught in New Zealand Patent No. 244107 may be employed instead.

Although the tank 14 is rigid, it need not be an integral or one-piece rigid construction. As taught in New Zealand Patent No. 244107, the tank 14 may be made of a number of smaller construction units that are bound and/or attached together to form the rigid tank 14.

The specific shape of the liner and tank is chosen such that the tank walls are able to support the flexible liner walls when the liner contains a volume of water. As shown in FIG. 1, the size of the liner 12 is comparable to the size of the tank 14. This is preferred because, as the liner expands when water is stored in the liner, the expansion is substantially immediately supported by the rigid tank walls.

In view of the above, the internal shape of the tank in relation of the shape of the flexible liner is of importance. For instance, if a cylindrical flexible liner is to be optimally supported, the tank inner walls should be cylindrical in shape and have a diameter only slightly larger than the liner. This is shown in FIG. 1.

It is also envisaged that aesthetically-pleasing outer tank walls may be employed. For example, a designed and/or textured outer tank surface may be used. This adaptability of the outer wall tank allows the water storage system to be blended in with its environment, or conversely, to be a focal point.

In the arrangement shown in FIG. 1, the liner 12 is installed into the tank 14 by inserting the liner 12 through the top of the tank 14. As such the base of the liner, shown as 16, is inserted into the tank 14 so as to abut the base of the tank, shown as 18.

To ensure the liner 12 is correctly installed, the liner base 16 includes a substantially rigid extension 20. In the preferred form, the substantially rigid extension 20 may allow fluid communication into and/or out of the liner 12. Most preferably, the substantially rigid extension 20 placed in the liner base 16 functions as a water outlet for the liner 12. For this purpose, the substantially rigid extension 20 may be a plastic tubing or pipe that is located so as to extend outwardly of the liner base 16 at one end, and to extend inwardly into the liner 12 at the other end.

The substantially rigid extension 20 is preferably joined to the flexible liner base by virtue of water-proof welding. As the liner 12 is installed inside the tank 14, the substantially rigid extension 20 is received in a key-in-lock relationship in an aperture 22 that is provided on the tank base 18. By designing the location and form of the extension/aperture as will be described below, the mating of the extension and the aperture substantially ensures the correct placement of the liner 12 in the tank 14.

The correct placement of the liner 12 inside the tank 14 may be dependent on the shapes chosen for the liner 12 and tank 14. As described, the placement must secure the liner 12 such that when it contains a volume of water, the walls of the liner 12 are adequately supported by the walls of the tank 14.

In the simplest form where both liner 12 and tank 14 share the same shape, the location of the substantially rigid extension 20 with respect to the liner base 16 will be the same as the location of the aperture 22 with respect to the tank base 18. This is shown in FIGS. 1 and 2, where both liner and tank have a cylindrical shape. Here, the substantially rigid extension 20 and aperture 22 are best located in the centre of the liner base 16 and tank base 18 respectively. Once the liner 12 is located inside the tank 14 and the substantially rigid extension 20 is placed through the aperture 22, the liner 12 will be correctly installed, as shown in FIG. 2. Although not shown, the tank 14 is then preferably covered using a lid that is joined to the liner 12 so as to seal the liner 12 within the tank 14.

Preferably where only one extension/aperture is designed for the water storage system, the extension and aperture are located in the centre of the liner base and tank base respectively. If the central location is not possible, it is preferable that two or more extension/aperture arrangements are provided.

However there may be configurations in which a central extension/aperture is not optimal, for instance where the tank and liner have a substantially square or rectangular cross-section. If one central extension/aperture is used here, the square cross-section liner may be installed with the edges of the liner pressed against the faces of the tank walls (that is the liner forms a diamond-shape within the square tank). When filled with water, the faces of the liner may not be adequately supported. In such an arrangement, the optimal layout may be to locate a number of extensions/apertures distributed close to the edges of the square cross-section.

FIGS. 3A-3F show alternative forms of the aperture layout with respect to the tank base 18. It will be appreciated that the liner 12 will have a similar shape to the tank and thus the layout of the substantially rigid extensions from the liner base will mirror the aperture layout shown in FIGS. 3A-3F. Of course the forms shown in these figures are only exemplary and are not restrictive. For instance, although all apertures are depicted as circles having the same diameter, this is not necessary. The aperture size/shape may be varied, particularly to suit the application of the extension that will be passing through the aperture. Persons skilled in the art will no doubt be able to precisely arrange the aperture/rigid extensions in a multitude of layouts.

In FIG. 3A, two apertures 22 distanced from one another are provided on the circular tank base 18. FIG. 3B shows a similar aperture layout, but on a tank base 18 having a square cross-section. The exact distance and angled locations of the apertures are of course not essential to the working of the invention.

FIG. 3C shows a circular tank base 18 having three apertures 22 laid out in a triangular arrangement. A similar triangular arrangement is shown in FIG. 3D for the square cross-section tank. Again the layout shown is not essential—the three apertures may be located in an L-arrangement if desired.

FIG. 3E shows a circular tank base 18 having four apertures 22 arranged in a square arrangement, and FIG. 3F shows a square tank base 18 having four squarely arranged apertures 22.

FIGS. 4 and 5 show an alternative embodiment of the water storage system. The liner 12 and tank 14 are structurally and functionally equivalent to the embodiment described with reference to FIGS. 1 and 2. Thus the construction, variants and modifications previously described with reference to FIGS. 1 and 2 are also applicable to the embodiment shown in FIGS. 4 and 5.

Referring to FIG. 4, the extension 20 of the liner is no longer provided on the base of the liner, but is instead located on the wall of the liner. In the preferred form shown, the extension 20 extends outwardly of the liner wall at about the middle of the liner height. This position can of course be varied, depending on the outcome to be achieved, as will be described below. To receive the extension 20, an aperture 22 is provided on the wall of the tank 14.

By placing the extension 20 on the liner wall, the positioning benefits similar to the embodiment of FIGS. 1 and 2 are realised. That is, once the liner 12 is inserted into the tank 14, and extension 20 is mated with aperture 22, the liner 12 will be correctly installed in the tank. However the additional benefit of locating the extension/aperture on the wall of the liner/tank is in terms of vertical support.

As is visible in FIG. 5, flexible liner 12 is held up in its erect position by locating the extension 20 through aperture 22. The vertical support afforded by this arrangement may avoid the liner 12 from folding or collapsing onto itself, for instance if the liner ages and sags. More importantly, where a heating element is provided within the liner 12 to heat the stored water, the support afforded by the extension/aperture mating may avoid the liner walls from collapsing and coming into contact with the heating element.

In view of the above, the extension 20 may be provided higher up the liner wall to provide optimum vertical support for the liner 12. In this case, the extension 20 is most preferably a water inlet into the liner 12. The extension 20 may alternatively be provided on the wall at a locating closer to the base. Although the amount of vertical support may be reduced in this arrangement, the extension 20 could be more optimally used as a water outlet for the liner 12. As before, two or more extensions/apertures may be employed.

FIG. 6 shows a cross-section of the joining of the liner 12 to the tank 14, in particular to the tank lid 26. The liner 12 includes a flange 24 that provides the liner 12 with a substantially rigid attachment point. The flange is preferable attached to the liner 12 by virtue of water-proof welding. The lid 26 may be made of polystyrene in favour of its light-weight and heat-insulation properties.

As is known from New Zealand Patent No. 244107, various devices may be located in the liner 12 to monitor and/or control the storage of water. For instance the liner 12 may be provided with heating element(s) and a thermostat to controllably heat the volume of water stored. Alternatively or additionally, level sensors may be provided. To provide a stable point of connection and support for such devices, a plate 28 may be provided on the lid 26. This would avoid having the devices resting directly on the preferred polystyrene lid 26.

The flange 24 will now be described with reference to both FIGS. 6 and 7. The flange acts as a rigid connector and includes a shoulder portion 30 and a neck portion 32. The shoulder portion 30 is welded to the liner 12 such that an opening through the flange 24 into the liner 12 is established. The welding must also be water-proof so as to prevent stored water from leaking out of the liner. The neck portion 32 is then located through the tank lid 26 so as to allow the liner 12 to be securely attached to the tank lid 26.

As indicated earlier, the substantially rigid extension 20 may allow for fluid communication into and/or out of the liner 12. Although not shown for the embodiment in the figures, the water inlet for the liner 12 is located about the lid 26, in particular through flange 24. The substantially rigid extension 20 thus functions as the water outlet. In this form, the substantially rigid extension 20 serves to both indicate/ensure a correct installation of liner 12, and to direct the flow of stored water out of the liner 12.

Referring to FIG. 8, a cross-sectional view of an example liner extension is shown. A fitting 20 a is attached to the liner base, for instance by water-proof welding, to detachably receive an extension 20 b. The fitting 20 a and the extension 20 b may be provided with screw threads, clips or the like to releasably secure the extension 20 b to the fitting 20 a. To afford substantial rigidity to the liner extension as a whole, both the fitting 20 a and the extension 20 b may be substantially rigid. Alternatively, either the fitting 20 a or the extension 20 b may be substantially rigid.

Preferably the fitting 20 a includes one or more aligning means to receive the extension 20 b. In the example shown in FIG. 8, the fitting 20 a is provided with a frustoconical section to receive a cone-shaped head on the extension 20 b. Other shapes of aligning means, such as pyramids or hemispheres, can be employed in the alternative.

The foregoing describes the invention including preferred forms thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof, as defined by the accompanying claims. 

1. A method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a base, the method comprising the steps of: providing at least one substantially rigid extension attached to and extending outwardly from the liner base; providing at least one aperture in the tank base; locating the liner inside the tank; and inserting the substantially rigid extension through the tank aperture, wherein the substantially rigid extension and aperture are positioned such that the liner is correctly positioned in the tank once the extension is inserted through the aperture.
 2. The method of installing a flexible liner as claimed in claim 1 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 3. The method of installing a flexible liner as claimed in claim 2 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 4. The method of installing a flexible liner as claimed in any preceding claim wherein the substantially rigid extension is located substantially in the centre of the liner base, and the aperture is located substantially in the centre of the tank base.
 5. The method of installing a flexible liner as claimed in any preceding claim wherein two or more extensions and apertures are provided.
 6. The method of installing a flexible liner as claimed in claim 5 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 7. A method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a base, the liner base having a substantially rigid extension extending outwardly and the tank base having an aperture to receive the substantially rigid extension, the method comprising the steps of: locating the liner inside the tank; and inserting the substantially rigid extension through the tank aperture, wherein the substantially rigid extension and aperture are positioned such that the liner is correctly positioned in the tank once the extension is inserted through the aperture.
 8. The method of installing a flexible liner as claimed in claim 7 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 9. The method of installing a flexible liner as claimed in claim 8 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 10. The method of installing a flexible liner as claimed in any one of claims 7 to 9 wherein the substantially rigid extension is located substantially in the centre of the liner base, and the aperture is located substantially in the centre of the tank base.
 11. The method of installing a flexible liner as claimed in any one of claims 7 to 10 wherein two or more extensions and apertures are provided.
 12. The method of installing a flexible liner as claimed in claim 11 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 13. A method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a wall, the method comprising the steps of: providing at least one substantially rigid extension attached to and extending outwardly from the liner wall; providing at least one aperture in the tank wall; locating the liner inside the tank; and inserting the substantially rigid extension through the tank aperture, wherein the substantially rigid extension and aperture are positioned such that the liner is correctly positioned in the tank once the extension is inserted through the aperture.
 14. The method of installing a flexible liner as claimed in claim 13 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 15. The method of installing a flexible liner as claimed in claim 14 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 16. The method of installing a flexible liner as claimed in any one of claims 13 to 15 wherein two or more extensions and apertures are provided.
 17. The method of installing a flexible liner as claimed in claim 16 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 18. A method of installing a flexible liner into a tank for water storage, wherein each of the liner and tank has a wall, the liner wall having a substantially rigid extension extending outwardly and the tank wall having an aperture to receive the substantially rigid extension, the method comprising the steps of: locating the liner inside the tank; and inserting the liner extension through the tank aperture, wherein the substantially rigid extension and aperture are positioned such that the liner is correctly positioned in the tank once the extension is inserted through the aperture.
 19. The method of installing a flexible liner as claimed in claim 18 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 20. The method of installing a flexible liner as claimed in claim 19 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 21. The method of installing a flexible liner as claimed in any one of claims 18 to 20 wherein two or more extensions and apertures are provided.
 22. The method of installing a flexible liner as claimed in claim 21 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 23. The method of installing a flexible liner as claimed in any one of the above claims wherein the substantially rigid extension is detachably received in a fitting that is attached to the liner.
 24. The method of installing a flexible liner as claimed in claim 23 wherein the fitting is provided with an aligning means to receive the substantially rigid extension.
 25. A water storage system comprising: a tank having a base, the tank base having at least one aperture; and a flexible liner having a base and positioned in the tank to store water, the liner base having at least one substantially rigid extension attached to and extending outwardly from the liner base; wherein the substantially rigid extension extends through the tank aperture to correctly position the liner in the tank.
 26. The water storage system as claimed in claim 25 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 27. The water storage system as claimed in claim 26 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 28. The water storage system as claimed in any one of claims 25 to 27 wherein the liner extension is located substantially in the centre of the liner base, and the aperture is located substantially in the centre of the tank base.
 29. The water storage system as claimed in any one of claims 25 to 28 wherein two or more extensions and apertures are provided.
 30. The water storage system as claimed in claim 29 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 31. A water storage system comprising: a tank having a wall, the tank wall having at least one aperture; and a flexible liner having a wall and positioned in the tank to store water, the liner wall having at least one substantially rigid extension attached to and extending outwardly from the liner wall; wherein the substantially rigid extension extends through the tank aperture to correctly position the liner in the tank.
 32. The water storage system as claimed in claim 31 wherein the substantially rigid extension allows fluid communication into or out of the liner.
 33. The water storage system as claimed in claim 32 wherein the substantially rigid extension is a length of pipe or tube attached to the liner.
 34. The water storage system as claimed in any one of claims 31 to 33 wherein two or more extensions and apertures are provided.
 35. The water storage system as claimed in claim 34 wherein at least one extension functions as a water inlet and at least another extension functions as a water outlet.
 36. The water storage system as claimed in any one claims 25 to 35 wherein the substantially rigid extension is detachably received in a fitting that is attached to the liner.
 37. The water storage system as claimed in claim 36 wherein the fitting is provided with an aligning means to receive the substantially rigid extension. 